.ac-container {
    width: 400px;
    margin: 10px auto 30px auto;
    text-align: left;
}

.ac-container label {
    font-family: 'BebasNeueRegular', 'Arial Narrow', Arial, sans-serif;
    padding: 5px 20px;
    position: relative;
    display: block;
    height: 30px;
    cursor: pointer;
    color: #777;
    text-shadow: 1px 1px 2px rgba(255, 255, 255, 0.8);
    line-height: 33px;
    font-size: 19px;
    background: #ffffff;
    background: -moz-linear-gradient(top, #ffffff 1%, #eaeaea 100%);
    background: -webkit-linear-gradient(top, #ffffff 1%, #eaeaea 100%);
    background: -o-linear-gradient(top, #ffffff 1%, #eaeaea 100%);
    background: -ms-linear-gradient(top, #ffffff 1%, #eaeaea 100%);
    background: linear-gradient(top, #ffffff 1%, #eaeaea 100%);
    box-shadow: 0px 0px 0px 1px rgba(155, 155, 155, 0.3), /*给周围一圈加上类似边框的效果*/ 1px 0px 0px 0px rgba(255, 255, 255, 1) inset, /*给每段最前面加上一点白条*/ 0px 2px 2px rgba(0, 0, 0, 0.1); /*最底下添加阴影*/
}

.ac-container label:hover {
    background: #fff;
}

.ac-container input:checked + label {
    background: #c6e1ec;
    color: #3d7489;
    text-shadow: 0px 1px 1px rgba(255, 255, 255, 0.6);
    box-shadow: 0px 0px 0px 1px rgba(155, 155, 155, 0.3),
    0px 2px 2px rgba(0, 0, 0, 0.1);
}

.ac-container label:hover:after {
    content: '';
    position: absolute;
    width: 24px;
    height: 24px;
    right: 13px;
    top: 7px;
    background: transparent url(../images/arrow_down.png) no-repeat center center;
}

.ac-container input:checked + label:hover:after {
    background-image: url(../images/arrow_up.png);
}

.ac-container input {
    display: none;
}

.ac-container article {
    background: rgba(255, 255, 255, 0.5);
    margin-top: -1px;
    overflow: hidden;
    height: 0px;
    position: relative;
    /* tips: write your code here */
}

.ac-container article p {
    font-style: italic;
    color: #777;
    line-height: 23px;
    font-size: 14px;
    padding: 20px;
    text-shadow: 1px 1px 1px rgba(255, 255, 255, 0.8);
}

.ac-container input:checked ~ article {
    /* tips: write your code here*/
}

.ac-container input:checked ~ article.ac-small {
    /* tips: write your code here*/
}

.ac-container input:checked ~ article.ac-medium {
    /* tips: write your code here*/
}

.ac-container input:checked ~ article.ac-large {
    /* tips: write your code here*/
}